Provided herein are methods for treatment of various skin afflictions in humans employing topically applied or orally dosed organophosphates. By reducing or eliminating Demodex organisms from affected skin areas, this method reduces clinical signs of the skin afflictions which are primarily due to allergic and vasomotor responses of the body to the organism and bacteria that are carried by the organism.
Rosacea, originally termed acne rosacea, is a chronic inflammatory skin condition most commonly affecting the face and eyelids of middle-aged adults. Clinical signs include erythema (redness), dryness, papules, pustules, and nodules either singly or in combination in the involved skin areas. Eyelid involvement may be manifested by mild conjunctival irritation or inflammation of the meibomian (oil) glands on the eyelid margin. Chronic eyelid irritation can result in loss of eyelashes. No visual impairment accompanies the eyelid irritation. Chronic involvement of the nose with rosacea in men can cause a bulbous enlargement known as rhinophyma. In the classic situation, the condition develops in adults between the ages of 30 and 50. While certain lesions of rosacea may mimic lesions of acne vulgaris, the processes are separate and distinct, the principal differences being the presence of comedones (whiteheads and blackheads) only in acne vulgaris and not in rosacea, the characteristic midfacial localization and flushing of rosacea not seen in acne, and the potential for eyelid involvement in rosacea which never occurs in acne. In fact, the clinical observation has been made that persons who have classic acne vulgaris as teenagers rarely, if ever, develop full-blown rosacea as adults.
Rosacea develops in four stages over several years, in spasms aggravated by variations in various conditions such as temperature, alcohol, spices, exposure to sunlight and emotions. The various disease stages can be described in terms of the stages: Stage 1: stage of erythema episodes. The patients have erythrosis spasms due to the sudden dilation of the arterioles of the face, which then take on a congestive, red appearance. These spasms are caused by the emotions, meals and temperature changes; Stage 2: stage of couperosis, i.e., of permanent erythema with telangiectasia. Certain patients also have edema on the cheeks and the forehead; Stage 3: inflammatory stage with appearance of inflammatory papules and pustules, but without affecting the sebaceous follicles and thus with absence of cysts and comedones; and Stage 4: rhinophyma stage. This late phase essentially affects men. The patients have a bumpy, voluminous red nose with sebaceous hyperplasia and fibrous reordering of the connective tissue.
Conventionally, rosacea is treated orally or topically with antibiotics such as tetracyclines, erythromycin or clindamycin, but also with vitamin A, salicylic acid, antifungal agents, steroids, anti-infectious agents such as benzoyl peroxide, or with isotretinoin in severe cases or most commonly with metronidazole (an antibacterial agent).
Metronidazole is known for its antiparasitic, antiprotozoan and antibacterial properties. It is especially used for treating Helicobacter pylori infections. It is also prescribed in the treatment of rosacea, for its advantageous properties on the inflammatory lesions of rosacea, specifically on papules and pustules. Metronidazole exerts selective toxicity towards anaerobic microorganisms and also hypoxic cells. On the latter, metronidazole is reduced to various derivatives that are capable of changing the structure of their DNA.
U.S. Patent Application 2013/0095051 filed Dec. 6, 2012 describes a method of treating rosacea using avermectin/metronidazole in a topical application. U.S. Pat. No. 5,952,372 describes a method for treating rosacea using ivermectin orally or topically in order to reduce and eliminate the parasite Demodex folliculorum present on the skin of patients.
Ivermectin belongs to the avermectin family, a group of macrocyclic lactones produced by the bacterium Streptomyces avermitilis. The avermectins especially include ivermectin, invermectin, avermectin, abamectin, doramectin, eprinomectin and selamectin. Ivermectin is known for its antiparasitic and anthelmintic properties. The antiparasitic activity is thought to be due to the opening of a chlorine channel in the membrane of the neurons of the parasite under the effect of an increased release of the neuromediator GABA (gammaaminobutyric acid), inducing neuromuscular paralysis that may lead to the death of certain parasites. Ivermectin also interacts with other chlorine channels, especially those dependent on the neuromediator GABA (gammaaminobutyric acid).
Ivermectin is conventionally administered in the dermatological treatment of endoparasitic manifestations such as onchocerciasis and myiasis. U.S. Pat. No. 6,133,310 describes the use of ivermectin in the treatment of rosacea in order to reduce and eliminate the parasite Demodex folliculorum present on the skin of patients. U.S. Pat. No. 6,133,310 describes the use of ivermectin in the treatment of rosacea in order to reduce and eliminate the parasite Demodex folliculorum present on the skin of patients.
However, these treatments and compounds have drawbacks such as irritation and intolerance phenomena, especially when they are administered for a prolonged period. All current rosacea treatments seem only to be suppressive and not curative, acting especially on the pustulous spasms occurring during the inflammatory stage.
According to the National Rosacea Society an estimated 16 million Americans have rosacea, yet only a small fraction are being treated. Rosacea's etiology is currently under dispute in the dermatology community. Rosacea (roe-ZAY-she-uh) is a common skin condition that causes redness in your face and often produces small, red, pus-filled bumps. Left untreated, rosacea tends to worsen over time. Rosacea signs and symptoms may flare up for a period of weeks to months and then diminish before flaring up again. Rosacea can be mistaken for acne, an allergic reaction or other skin problems. While there's no cure for rosacea, current treatments can only help to control and reduce the signs and symptoms of the condition.
Rosacea is typically observed in individuals after the age of thirty as redness on the cheeks, nose, chin or forehead that may come and go. In some cases, rosacea may also occur on the neck, chest, scalp or ears. Over time the redness tends to become ruddier and more persistent, and visible blood vessels may appear. Left untreated, bumps and pimples often develop and in severe cases the nose may grow swollen and bumpy from excess tissue. This is the condition known as rhinophyma. In many rosacea patients the eyes are also affected, feeling irritated and appearing watery or bloodshot.
Although rosacea can affect all segments of the population, individuals with fair skin who tend to flush or blush easily are believed to be at greatest risk. The disease is more frequently diagnosed in women, but more severe symptoms tend to be seen in men. Rosacea can vary substantially from one individual to another and in most cases some rather than all of the potential signs and symptoms appear. According to a consensus committee and review panel of 17 medical experts worldwide, rosacea always includes at least one of the following primary signs, and various secondary signs and symptoms may also develop.
Primary Signs of rosacea include one or more of the following observable symptoms: (1) Flushing: Many people with rosacea have a history of frequent blushing or flushing. This facial redness may come and go, and is often the earliest sign of the disorder; (2) Persistent Redness Persistent facial redness is the most common individual sign of rosacea, and may resemble a blush or sunburn that does not go away; (3) Bumps and Pimples: Small red solid bumps or pus-filled pimples often develop. While these may resemble acne, blackheads are absent and burning or stinging may occur; (4) Visible Blood Vessels: In many people with rosacea, small blood vessels become visible on the skin.
Other Potential Signs and Symptoms include: (1) Eye Irritation. In many people with rosacea, the eyes may be irritated and appear watery or bloodshot, a condition known as ocular rosacea. The eyelids also may become red and swollen, and styes are common. Severe cases can result in corneal damage and vision loss without medical help. (2) Burning or Stinging. Burning or stinging sensations may often occur on the face. Itching or a feeling of tightness may also develop. (3) Dry Appearance. The central facial skin may be rough, and thus appear to be very dry. (4) Plaques. Raised red patches, known as plaques, may develop without changes in the surrounding skin. Skin (5) Thickening. The skin may thicken and enlarge from excess tissue, most commonly on the nose. This condition, known as rhinophyma, affects more men than women. (6) Swelling. Facial swelling, known as edema, may accompany other signs of rosacea or occur independently. (7) Signs Beyond the Face. Rosacea signs and symptoms may also develop beyond the face, most commonly on the neck, chest, scalp or ears.
Subtypes of rosacea: Subtype 1: (erythematotelangiectatic rosacea), characterized by flushing and persistent redness, and may also include visible blood vessels. Subtype 2: (papulopustular rosacea), characterized by persistent redness with transient bumps and pimples. Subtype 3: (phymatous rosacea), characterized by skin thickening, often resulting in an enlargement of the nose from excess tissue. Subtype 4: (ocular rosacea), characterized by ocular manifestations such as dry eye, tearing and burning, swollen eyelids, recurrent styes and potential vision loss from corneal damage.
Many patients experience characteristics of more than one subtype at the same time, and those often may develop in succession. While rosacea may or may not evolve from one subtype to another, each individual sign or symptom may progress from mild to moderate to severe. Early diagnosis and treatment are recommended.
As will be understood from the foregoing, methods of treating dermatological conditions, such as rosacea, are needed. Treatment methods are needed, for example, providing curative or long-term suppressive treatments capable of treating symptoms beyond the pustulous spasms which occur during the inflammation stage. Such treatment methods may be able to kill or inactivate the parasites or bacteria causing the allergic or vasomotor responses. Additionally, treatments exhibiting a combination enhanced efficacy and speed of treatment, low toxicity and reduced side effects would be useful and beneficial.